The present invention relates to a novel ophthalmic solution for intraocular pressure adjustment, and more particularly to an ophthalmic solution for intraocular pressure adjustment useful for treatment of ocular hypertension and glaucoma.
Hitherto, a pilocarpine ophthalmic solution has been employed as agents for adjusting intraocular pressure for use in ocular hypertension and glaucoma. It is known that the pilocarpine ophthalmic solution decreases the intraocular pressure, but acts on sphincter of pupil and ciliary body and has side effects such as visual darkness due to miosis, disorder of accommodation and conjunctival injection. Such side effects bring about a serious danger particularly in working of persons who engage in communication and transportation undertakings. Also, in case of a middle-aged cataract patient, the side effects increase visual disorder due to miosis. From viewpoint of these defects, there has been desired development of intraocular pressure adjusting agents for ocular hypertension and glaucoma to be replaced by the pilocarpine ophthalmic solution.
An epinephrine ophthalmic solution was developed on the basis of such a demand, but has a side effect such as conjunctival injection, pain in eye-brow portion or allergic blepharoconjunctivitis and in some cases, brings about intraocular pressure rise due to mydriasis. Therefore, the epinephrine ophthalmic solution is not much employed. Also, it has been attempted clinically to use surface anesthetics and psychotropic drugs as drugs which produce decrease of intraocular pressure of glaucoma eye, but any drugs have not been put to practical use.
In recent years, .beta.-blocking agents are watched in this region, and it was found that 2-acetyl-7-(2-hydroxy-3-isopropylaminopropoxy)benzofuran (hereinafter referred to as "befunolol") which is one of .beta.-blocking agents and is increasing in its estimation as a cardiovascular agent, is also useful as an ophthalmic agent for treating ocular hypertension and glaucoma.
Fundamental properties required for pharmaceuticals are effectiveness, safety and stability. Therefore, in case of an ophthalmic solution for the treatment of ocular hypertension and glaucoma, the ophthalmic solution is required to have an effect of decreasing intraocular pressure and a proper durability of the effect, and moreover to have no side effects, that is, to have no effect on accommodation mechanism of pupil and refraction and to give no irritation, and also to be stable as preparations. Estimating the above-mentioned befunolol ophthalmic solution from these points of view, it is not yet a complete ophthalmic solution, though its effectiveness and safety are substantiated to some extent by Tane et al as reported in Japanese Review of Clinical Ophthalmology, Vol. 73, No. 3, 35-40 (1979).
It is an object of the present invention to provide an ophthalmic solution of befunolol which can be used safely with large effect and stability.
A further object of the invention is to provide an ophthalmic solution for intraocular pressure adjustment, which can exhibit the effects in a lower concentration of the effective component with reduced local irritation and is stable for a long term.
These and other objects of the invention will become apparent from the description hereinafter.